package day07;

import java.util.Random;

public class VerificationCode2 {
    public static void main(String[] args) {
        String code = code(4);
        System.out.println("验证码为:"+code);
    }
    public static String code(int len){
        String codes ="";
        char[] cha ={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t',
                'u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N',
                'O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7',
                '8','9','0'};
        Random rand =new Random();
        for (int i =1;i<=len;i++){
            int index = rand.nextInt(cha.length);
            codes+=cha[index];
        }
        return codes;
    }
}
